The simple pleasures of watching Godzilla or Ultraman doing battle on Saturday afternoon television have proved difficult to re-create since their heyday in the '70s and '80s. Big-budget Hollywood attempts to replicate the experience tend to not just be failures, but disastrous, highly polished failures on an epic scale: Roland Emmerich's 1998 take on Godzilla, for instance, or Michael Bay's Transformers series.

But director Guillermo del Toro knows that the charm in the clash of scale- or armor-plated titans isn't necessarily tied to the low budgets and laughable production design of those guilty-pleasure TV shows. And with Pacific Rim, he cracks the code.

It was probably only a matter of time before del Toro tackled this genre; his career, on the one hand, has been largely devoted to monsters of one kind or another, and their place as stand-ins for the things that scare us in the real world. Japanese movie monsters, on the other, were little more than atomic-age fears of mass destruction made flesh — made rubber suits, anyway.

In this modern-day update of the genre those monsters launched, del Toro and writer Travis Beacham trade in nuclear anxiety for more top-of-mind worries about climate change. The monstrous creatures rising from the deep in Pacific Rim are even assigned categories according to their size and power, mirroring those we give nowadays to hurricanes; a Category 4 beast can easily take out a major city, and a rarely seen Category 5 is a destructive force of nearly unimaginable proportions.

A speedy prologue wastes no time setting things up, which (thankfully) allows the movie to avoid the 2.5-hour-plus running times currently plaguing event movies at the multiplex. The Kaiju — this near-future society is pop-culture-savvy enough to have used Japanese movie-monster nomenclature for the creatures — come from an interdimensional portal on the ocean floor known as The Breach. And like rising sea levels, they've been taking out coastal cities. As the periodic appearances of these creatures have shown no signs of abating, humanity has banded together to create "Jaegers" — 25-story battlebots operated by dual pilots who must temporarily merge minds to drive the things.

Del Toro quite rightly declines to take any of this nearly as seriously as the characters in the movie do. For them, the war with the Kaiju, which is in its seventh year as the movie begins, isn't just life or death; it's life or worldwide apocalypse. But del Toro is making entertainment, and even though his battles rage at night amid gloomy seas, the movie doesn't share the grim, humorless tone of the summer's other would-be blockbusters.

So while Jaeger pilot Raleigh (Charlie Hunnam) may be the dashing hero, his partner Mako (Rinko Kikuchi) the emotional core, and Jaeger Corps head honcho Stacker (Idris Elba) the authoritative father figure, it's Charlie Day, as Kaiju biologist Newton Geiszler, who best exemplifies what makes Pacific Rim work so well.

Geizler's scenes are funny — especially once he hooks up with the closest thing the movie has to a human villain, played by an actor whose big-reveal scene is too good to even mention him by name here. But they're not just comic relief; without Geiszler and his talents, the full plan of the resistance can't come to fruition. In making him so central, del Toro weaves together the film's light and dark aspects so that the proceedings can't be dominated by either.

He also keeps things limber with a steady stream of well-integrated cultural references. Early on, one pilot quotes Han Solo to another; one of the first shots of Hong Kong, where much of the movie's pivotal battles take place, suggests the look and feel of Blade Runner; Stacker's speech before the climactic showdown evokes the St. Crispin's Day monologue from Henry V. (He never says "Once more unto the breach," from that play's other big soliloquy, but given how many times the film refers to The Breach elsewhere, he hardly needs to.)

As you'd expect in a del Toro film, the production design — particularly that of the monsters — is gorgeously detailed. It's a shame, then, that the only tired modern action trope the director falls victim to is the one that sometimes takes him too close to the action in battle sequences, making them a little confusing and blunting the impact of some of that design work.

Quibbles aside, Pacific Rim delivers plenty of the thing that's been lacking in this summer's event movies: fun. Monsters, robots, grand heroism and a few clever jokes: Sounds like a perfect Saturday afternoon to me.